Recently, novel light sources such as light emitting diodes (LEDs) and organic light emitting diodes (OLEDs) have received attention as illuminating display devices while rapidly replacing existing light sources. The illuminating display devices include parts such as a reflector, a reflector cup, a scrambler, a housing, and the like. The material used in the manufacture of the parts as described above should be resistant against a high temperature for a long period of time and also minimize reflectance and whiteness deterioration caused by yellowing.
Polyesters, as well as copolymers and/or mixtures thereof, can have useful properties such as heat resistance, impact resistance, moldability, and the like, such that they are variously applied as an interior/exterior material. Polyester resin has also been used as a material for illuminating display devices. For example, a high heat resistant polyester resin is not deformed at a high temperature and has excellent discoloration resistance, such that the high heat resistant polyester resin has been used as a part of the LED for light efficiency. However, when the high heat resistant polyester resin is exposed to high temperature and high humidity conditions for a long period of time, it is difficult to maintain reflectance and discoloration resistance, such that long term light stability and reliability may be deteriorated.
A polyamide based resin composition having excellent heat resistance and reflectance by mixing an additive such as a light stabilizer, or the like, in order to improve light stability and discoloration resistance of a resin has been disclosed in U.S. Pat. No. 7,009,029. However, in this case, mechanical properties may be deteriorated by the additive, and it may be impossible to secure long term light stability and reliability.
Therefore, there is a need for a thermoplastic resin that can be used in the manufacture of illuminating display devices and can be exposed to high temperature and high humidity conditions for a long period of time.